JP4986277B2 - Wheel bearing device - Google Patents

Description

  The present invention relates to a wheel bearing device that rotatably supports a wheel of an automobile or the like, and more particularly to a wheel bearing device that achieves strength and high rigidity and a long bearing life.

  2. Description of the Related Art Conventionally, a wheel bearing device for supporting a wheel of an automobile or the like is such that a hub wheel for mounting a wheel is rotatably supported via a rolling bearing, and there are a drive wheel and a driven wheel. For structural reasons, an inner ring rotation method is generally used for driving wheels, and an inner ring rotation method and an outer ring rotation method are generally used for driven wheels. As the wheel bearing device, a double-row angular ball bearing having a desired bearing rigidity, exhibiting durability against misalignment, and having a small rotational torque from the viewpoint of improving fuel efficiency is often used. On the other hand, double row tapered roller bearings are used in vehicles such as off-road cars and trucks that have a heavy vehicle body weight.

  Further, the wheel bearing device has a structure called a first generation in which a wheel bearing composed of a double row angular ball bearing or the like is fitted between a knuckle and a hub wheel constituting a suspension device. Second generation structure in which body mounting flange or wheel mounting flange is formed directly on the outer periphery of the member, third generation structure in which one inner rolling surface is directly formed on the outer periphery of the hub wheel, or hub wheel, etc. It is roughly classified into a fourth generation structure in which the inner rolling surface is directly formed on the outer periphery of the outer joint member of the speed universal joint.

  In such a wheel bearing device, conventionally, both rows of bearings have the same specification, so that they have sufficient rigidity when stationary, but the optimum rigidity is not always obtained when the vehicle turns. That is, the position of the vehicle weight when stationary is determined so that it acts on the approximate center of the double row rolling bearing, but when turning, the opposite side of the turning direction (when turning right, the vehicle A large radial load or axial load is applied to the left axle. Therefore, at the time of turning, it is effective to increase the rigidity of the outer bearing row rather than the inner bearing row. Therefore, a wheel bearing device shown in FIG. 5 is known as a wheel bearing device that has improved rigidity during turning without increasing the size of the device.

  This wheel bearing device 50 has a vehicle body mounting flange 51c integrally attached to a knuckle (not shown) on the outer periphery, and an outer side in which double row outer rolling surfaces 51a and 51b are formed on the inner periphery. A member 51 and a wheel mounting flange 53 for mounting a wheel (not shown) at one end are integrally formed, and one inner rolling surface 52a facing the double row outer rolling surfaces 51a and 51b on the outer periphery. The hub wheel 52 having a small-diameter step portion 52b extending in the axial direction from the inner rolling surface 52a and the small-diameter step portion 52b of the hub wheel 52 are externally fitted to the double-row outer rolling surfaces 51a and 51b. An inner member 55 composed of an inner ring 54 formed with the other inner rolling surface 54a facing each other, double rows of balls 56, 57 accommodated between both rolling surfaces, and these double rows of balls 56, 57 A retainer 58 for freely rolling It is composed of a double row angular contact ball bearing with a 9.

  The inner ring 54 is fixed in the axial direction by a caulking portion 52c formed by plastically deforming a small diameter step portion 52b of the hub wheel 52 radially outward. Seals 60 and 61 are attached to the opening of the annular space formed between the outer member 51 and the inner member 55, leakage of the lubricating grease sealed inside the bearing, and rainwater from the outside into the bearing. And dust are prevented from entering.

Here, the pitch circle diameter D1 of the outer side ball 56 is set larger than the pitch circle diameter D2 of the inner side ball 57. Along with this, the inner rolling surface 52a of the hub wheel 52 is expanded in diameter than the inner rolling surface 54a of the inner ring 54, and the outer rolling surface 51a on the outer side of the outer member 51 is also rolled on the inner side. The diameter is larger than that of the surface 51b. The outer side balls 56 are accommodated more than the inner side balls 57. In this way, by setting the pitch circle diameters D1 and D2 to D1> D2, the rigidity is improved not only when the vehicle is stationary but also when turning, and the life of the wheel bearing device 50 can be extended. it can.
JP 2004-108449 A

  In such a conventional wheel bearing device 50, the pitch circle diameter D1 of the outer ball 56 is set to be larger than the pitch circle diameter D2 of the inner ball 57, and accordingly, the inner rolling of the hub wheel 52 is performed. The surface 52a is larger in diameter than the inner rolling surface 54a of the inner ring 54. As a result, the rigidity of the outer bearing row is improved, and the life of the wheel bearing device 50 can be extended. However, the rigidity of the inner side bearing row is insufficient with respect to the rigidity of the outer side bearing row, and the outer side of the hub wheel 52 is formed with a larger diameter. It was impossible to reduce the weight of the device.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a wheel bearing device that solves the conflicting problems of light weight and compactness and strength and high rigidity of the device.

In order to achieve the object, the invention according to claim 1 of the present invention has a vehicle body mounting flange integrally attached to the knuckle on the outer periphery, and a double row outer rolling surface is formed on the inner periphery. An outer member, and a wheel mounting flange for mounting a wheel at one end are integrally formed, one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and an axis from the inner rolling surface Hub wheel formed with a small-diameter step portion extending in the direction, and the other inner rolling surface that is press-fitted into the small-diameter step portion of the hub wheel through a predetermined shimoshiro and faces the outer rolling surface of the double row on the outer periphery An inner member formed of an inner ring formed with an inner ring, and a double-row rolling element that is rotatably accommodated between both rolling surfaces of the inner member and the outer member. Starting from the running surface, from the inner base of the wheel mounting flange to the small diameter step In the wheel bearing device in which a predetermined hardened layer is formed by induction hardening, the outer-side rolling element is a ball and the inner-side rolling element is a tapered roller among the double-row rolling elements, and the inner-side tapered roller Is formed smaller than the pitch circle diameter of the outer-side ball, and an axial portion is formed extending in the axial direction from the groove bottom portion of the inner raceway surface of the hub wheel to the small-diameter step portion. are, together with the tapered step portion is formed between the shoulder portion which is matched to the shaft-like portion and the inner ring, conical recess is formed at an end portion of the outer side of the hub wheel, the The depth of the recess is the depth from the bottom of the inner rolling surface to the vicinity of the stepped portion, and the thickness of the ball on the inner rolling surface in the contact angle direction is the groove of the inner rolling surface. thicker than the thickness of the bottom portion, and the depth of the hardened layer It is set more than doubled.

Thus, an outer member having a vehicle body mounting flange on the outer periphery, a hub wheel having a wheel mounting flange at one end, an inner member made of an inner ring press-fitted into the hub wheel, and the inner member and the outer member. In a third-generation wheel bearing device comprising a double row rolling element housed between members, the outer side rolling element of the double row rolling element is a ball and the inner side rolling element is a tapered roller. Yes, the pitch circle diameter of the inner side tapered roller is set smaller than the pitch circle diameter of the outer side ball, and extends in the axial direction from the groove bottom of the inner raceway surface of the hub wheel to the small diameter step. A shaft-shaped portion is formed, a tapered step is formed between the shaft-shaped portion and the shoulder that is abutted against the inner ring, and a mortar-shaped recess is formed at the outer end of the hub wheel. It is, the depth of this recess, beyond the groove bottom of the inner raceway surface Is the depth up to around section, the thickness of the contact angle direction of the ball in the inner raceway surface is thicker than the thickness of the groove bottom of the inner raceway surface, and more than twice the depth of the hardened layer Therefore, it is possible to provide a wheel bearing device that simultaneously solves the conflicting problems of light weight, compactness, and high rigidity of the device, and that has improved strength and extended life.

  Preferably, as in the invention according to claim 2, the wall thickness in the contact angle direction of the ball on the inner raceway surface of the hub wheel is set in a range of 0.2 to 0.3 of the diameter of the portion. If so, weight reduction can be achieved while securing the strength and rigidity of the hub wheel corresponding to the use conditions.

Further, as in a third aspect of the invention, the inner ring is axially applied with a predetermined preload by a crimped portion formed by plastically deforming an end portion of the small diameter step portion radially outward. If it is fixed to, it is possible to further reduce the weight and size, and to maintain the preload set at the initial stage over a long period of time.

The wheel bearing device according to the present invention has an outer member integrally formed with a vehicle body mounting flange to be attached to the knuckle on the outer periphery, a double row outer rolling surface formed on the inner periphery, and a wheel at one end. A wheel mounting flange is integrally formed, and one inner rolling surface facing the outer rolling surface of the double row is formed on the outer periphery, and a small diameter step portion extending in the axial direction from the inner rolling surface is formed. And an inner ring formed by press-fitting the hub wheel into a small-diameter step portion of the hub ring via a predetermined scissors and having the other inner rolling surface facing the outer rolling surface of the double row formed on the outer periphery. Member, and a double row rolling element that is rotatably accommodated between the rolling surfaces of the inner member and the outer member, and includes the inner rolling surface of the hub wheel and the wheel mounting flange. Specified by induction hardening over the small diameter step from the base on the inner side In the wheel bearing device in which the hardened layer is formed, out of the double row rolling elements, the outer side rolling element is a ball, and the inner side rolling element is a tapered roller, and a pitch circle diameter of the inner side tapered roller has a pitch circle diameter. A shaft-shaped portion that is set to a diameter smaller than the pitch circle diameter of the outer-side ball and extends in the axial direction from the groove bottom portion of the inner raceway surface of the hub wheel to the small-diameter step portion is formed. A tapered step is formed between the portion and the shoulder abutted against the inner ring, and a mortar-shaped recess is formed at the outer end of the hub wheel, and the depth of the recess Is the depth of the inner rolling surface beyond the groove bottom to the vicinity of the step, and the thickness of the ball on the inner rolling surface in the contact angle direction is greater than the thickness of the groove bottom portion of the inner rolling surface. thicker, and, what is set to be twice or more the depth of the hardened layer , It is possible to solve the contradictory problem of weight and size and a high rigidity of the apparatus at the same time, to provide a wheel bearing apparatus which aimed to extend the life of increasing the strength.

A body mounting flange for mounting to the knuckle on the outer periphery is integrated, an outer member with a double row outer raceway formed on the inner periphery, and a wheel mounting flange for mounting the wheel on one end is integrated. A hub wheel having one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, a small diameter step portion extending in the axial direction from the inner rolling surface, and a small diameter of the hub wheel An inner member consisting of an inner ring that is press-fitted into a stepped portion and has the other inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and both rolling of the inner member and the outer member And a double row of balls accommodated in a freely rolling manner between the surfaces, including the inner rolling surface of the hub wheel, from the inner side base of the wheel mounting flange to the small diameter step by induction hardening. A predetermined hardened layer is formed, and the end portion of the small-diameter step portion is radially outward. In the wheel bearing device in which the inner ring is fixed in the axial direction with respect to the hub ring by a caulking portion formed by elastically deforming, the outer side rolling elements of the double row rolling elements are balls and inner side rolling elements. The moving body is a tapered roller, and the pitch circle diameter of the inner side tapered roller is set to be smaller than the pitch circle diameter of the outer side ball, and the small diameter step portion is formed from the groove bottom of the inner raceway surface of the hub ring. A shaft-shaped portion extending in the axial direction is formed, and a tapered step is formed between the shaft-shaped portion and a shoulder portion that abuts against the inner ring, and an outer side of the hub wheel is formed . A mortar-shaped recess is formed at the end, and the depth of the recess is the depth from the groove bottom of the inner rolling surface to the vicinity of the stepped portion, and the contact angle of the ball on the inner rolling surface The wall thickness in the direction is greater than the wall thickness at the bottom of the groove on the inner rolling surface. Ku, and it is set to is set to more than double the depth of the hardened layer.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a reference example of a wheel bearing device according to the present invention, and FIG. 2 is an enlarged view of a single hub wheel of FIG. In the following description, the side closer to the outer side of the vehicle in a state assembled to the vehicle is referred to as the outer side (left side in the drawing), and the side closer to the center is referred to as the inner side (right side in the drawing).

  This wheel bearing device is for a driven wheel called the third generation, and includes an inner member 1 and an outer member 2, and a plurality of balls 3 accommodated so as to roll between both members 1 and 2. A tapered roller 4 is provided. The inner member 1 includes a hub ring 5 and an inner ring 6 press-fitted into the hub ring 5 through a predetermined shimiro.

  The hub wheel 5 integrally has a wheel mounting flange 7 for mounting a wheel (not shown) at one end portion, one (outer side) arcuate inner rolling surface 5a on the outer periphery, and this inner rolling. A small-diameter step portion 5b is formed through an axial portion 8 extending in the axial direction from the surface 5a. Hub bolts 7a are planted on the wheel mounting flange 7 in a circumferentially uniform manner, and circular holes 7b are formed between the hub bolts 7a. The circular hole 7b not only contributes to weight reduction, but also a fastening jig such as a wrench can be inserted from the circular hole 7b in the assembly / disassembly process of the apparatus, and the work can be simplified.

  The inner ring 6 is formed with the other (inner side) tapered inner rolling surface 6a on the outer periphery, a large collar 6b for guiding the tapered roller 4 to the large diameter side of the inner rolling surface 6a, and a small diameter side In addition, a small scissors 6c for preventing the tapered roller 4 from falling off is formed. The inner ring 6 is press-fitted into the small-diameter step portion 5b of the hub wheel 5 through a predetermined shimiro, and a predetermined preload is applied by a crimping portion 9 formed by plastically deforming an end portion of the small-diameter step portion 5b. In the applied state, it is fixed in the axial direction. As a result, it is possible to reduce the weight and size, and to maintain the initially set preload over a long period of time.

  The hub wheel 5 is formed of medium-high carbon steel containing carbon of 0.40 to 0.80 wt% such as S53C, and includes an inner rolling surface 5a and an inner side of a wheel mounting flange 7 on which an outer seal 12 described later is in sliding contact. The hardened layer 23 is formed in the range of 58 to 64 HRC by induction hardening from the base portion 7c to the small diameter step portion 5b (indicated by cross hatching in the figure). The caulking portion 9 is kept in the surface hardness after forging. Thereby, it has sufficient mechanical strength with respect to the rotational bending load applied to the wheel mounting flange 7, and the fretting resistance of the small-diameter step portion 5 b serving as the fitting portion of the inner ring 6 is improved, and caulking is performed. There is no generation of minute cracks or the like during processing, and the plastic processing of the crimped portion 9 can be performed smoothly. The inner ring 6, the ball 3 and the tapered roller 4 are made of high carbon chrome steel such as SUJ2, and are hardened in the range of 58 to 64HRC to the core by quenching.

  The outer member 2 integrally has a vehicle body mounting flange 2c to be attached to a knuckle (not shown) constituting a suspension device on the outer periphery, and an outer member facing the inner rolling surface 4a of the hub wheel 4 on the inner periphery. An arcuate outer rolling surface 2a on the side and an inner tapered outer rolling surface 2b facing the inner rolling surface 5a of the inner ring 5 are integrally formed. This outer member 2 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the double row outer rolling surfaces 2a and 2b have a surface hardness in the range of 58 to 64HRC by induction hardening. Has been cured. And the some ball | bowl 3 and the tapered roller 4 are accommodated rotatably via the holder | retainer 10 and 11 between both rolling surface 2a, 4a and 2b, 5a. In addition, a seal 12 and a magnetic encoder 13 are attached to the opening of the annular space formed between the outer member 2 and the inner member 1, and leakage of grease sealed inside the bearing to the outside Prevents rainwater and dust from entering the bearing.

  In the present embodiment, the pitch circle diameter PCDi of the four rows of inner side tapered rollers is set to be smaller than the pitch circle diameter PCDo of the three rows of balls on the outer side. As a result, the outer diameter D on the inner side of the outer member 2 can be set to a small diameter. By using the tapered rollers 4, the knuckle size can be reduced without reducing the basic load rating of the inner rolling element row. The rigidity of the rolling element row portion on the inner side is increased while reducing the size and weight of the device.

  Further, on the outer periphery of the hub wheel 5, there are a shaft-shaped portion 8 formed with a small diameter from the counter portion 14 that gradually decreases in diameter toward the inner side from the inner rolling surface 5a, and an inner ring 6 through the step portion 8a. A small-diameter step portion 5b is formed through the shoulder portion 8b to be abutted. Further, along with the difference in pitch circle diameters PCDo and PCDi, the inner rolling surface 5a of the hub wheel 5 is larger than the inner rolling surface 6a of the inner ring 6.

  In the outer member 2, the outer side outer rolling surface 2 a has a larger diameter than the inner side outer rolling surface 2 b with the difference in pitch circle diameters PCDo and PCDi, and the outer side outer rolling surface 2 a is cylindrical. The shoulder portion 16 on the small diameter side is continued through the shoulder portion 15 and the step portion 15a to the outer side rolling surface 2b on the inner side.

  Here, a mortar-shaped recess 17 extending in the axial direction is formed at the outer side end of the hub wheel 5. This recess 17 is formed by forging, and its depth is at least up to the vicinity of the groove bottom of the inner side rolling surface 5a on the outer side, and the thickness of the outer side of the hub wheel 5 corresponding to this recess 17 Is formed to be substantially uniform. That is, when a moment load is applied to the wheel mounting flange 7, it is considered that the hub wheel 5 is deformed starting from the contact angle α of the outer-side ball 3. Focused on the wall thickness.

  As shown in an enlarged view in FIG. 2, the base portion 7c of the wheel mounting flange 7 serving as the seal land portion is formed in an arc surface having a predetermined radius of curvature, and the minimum thickness t1 of the base portion 7c and its portion As a result of obtaining the rigidity of the hub wheel 5 by FEM analysis from the relationship with the diameter d1 of the hub, the minimum thickness t1 is set in the range of 0.2 ≦ t1 / d1 ≦ 0.3, so that the hub corresponding to the use conditions Weight reduction can be achieved while securing the strength and rigidity of the wheel 5. When the minimum thickness t1 of the base portion 7c is less than 20% of the diameter d1 of the portion, the deformation becomes large and desired rigidity cannot be obtained. On the other hand, even if the minimum thickness t1 exceeds 30% of the diameter d1, the rigidity is not increased so much, which is not preferable because it causes a weight increase.

  Furthermore, in this embodiment, in order to prevent the outer peripheral surface of the hub wheel 5 from being cracked by induction hardening, the minimum thickness t1 of the base portion 7c is 2 which is the effective hardened layer depth of the hardened layer 23. It is set to be more than double. Similarly to the base portion 7c of the wheel mounting flange 7, the relationship between the wall thickness t2 of the ball 3 on the inner rolling surface 5a in the contact angle α direction and the diameter (ball contact diameter) t2 of the portion is 0.2. ≦ t2 / d2 ≦ 0.3 and at least twice the effective hardened layer depth in the hardened layer 23. Here, the effective hardened layer depth is set in a range of 2 to 5 mm (about 3.5 mm).

  In the wheel bearing device having such a configuration, the pitch circle diameter PCDo of the outer side balls 3 is set to be larger than the pitch circle diameter PCDi of the inner side tapered rollers 4, and the number of balls 3 is set correspondingly. Therefore, the bearing rigidity of the outer side portion is increased, and a recess 17 is formed at the outer end of the hub wheel 5, and the thicknesses t1 and t2 are set within a predetermined range corresponding to the recess 17. ing. And since the outer shell is set to a predetermined shape and size so that the outer side of the hub wheel 5 has a substantially uniform thickness, and the depth of the hardened layer 23 is set to a predetermined range, It is possible to provide a wheel bearing device that solves the conflicting problems of light weight, compactness, and high rigidity at the same time, and increases the strength and extends the service life.

Figure 3 is a longitudinal sectional view showing an implementation form of the wheel bearing apparatus of the present invention, FIG. 4 is an enlarged view of the wheel hub itself of FIG. Note that this embodiment is basically different from the above-described reference example (FIG. 1) only in the configuration of the hub wheel, and the same reference numerals are given to other identical parts, identical parts, or parts having the same function. In addition, the detailed description is omitted.

  This wheel bearing device is for a driven wheel called a third generation, and includes an inner member 18 and an outer member 2, a plurality of balls 3 accommodated in a freely rolling manner between the two members 18 and 2, and A tapered roller 4 is provided. The inner member 18 includes a hub ring 19 and an inner ring 6 that is press-fitted into the hub ring 19 through a predetermined shimiro.

  The hub wheel 19 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon, such as S53C, and is formed deeper than the mortar-shaped recess 17 (shown by a two-dot chain line) at the end on the outer side. A recessed portion 20 is formed. The depth of the recess 20 is a depth from the groove bottom portion of the inner rolling surface 5a to the vicinity of the step portion 22 beyond the shaft portion 21. The outer shape of the hub wheel 19 is formed so as to have a uniform thickness corresponding to the recess 20, and a predetermined hardened layer 24 is formed on the outer periphery thereof (shown by cross hatching in the figure). ). That is, as shown in an enlarged view in FIG. 4, in the present embodiment, the minimum thickness t1 of the base portion 7c and the thickness t2 of the inner rolling surface 5a in the contact angle α direction are the minimum thickness of the inner rolling surface 5a. (Thickness at groove bottom diameter d0 position) The thickness is set to be larger than t0, and the minimum thickness t1 of the base portion 7c of the wheel mounting flange 7 serving as the seal land portion and the thickness t2 in the contact angle α direction are In the range of 0.2 to 0.3 of the diameters d1 and d2, the thickness t3 of the bottom of the recess 20 is formed substantially the same as the thicknesses t1 and t2 on the outer side from the contact angle α. Furthermore, these wall thicknesses t1, t2, and t3 are set to be twice or more the effective hardened layer depth in the hardened layer 23. As a result, it is possible to achieve further weight reduction while ensuring the rigidity of the hub wheel 19, and it is possible to increase the strength by preventing burning cracks.

  The embodiment of the present invention has been described above, but the present invention is not limited to such an embodiment, and is merely an example, and various modifications can be made without departing from the scope of the present invention. Of course, the scope of the present invention is indicated by the description of the scope of claims, and further, the equivalent meanings described in the scope of claims and all modifications within the scope of the scope of the present invention are included. Including.

  The wheel bearing device according to the present invention can be applied to a third-generation wheel bearing device for a driven wheel.

It is a longitudinal cross-sectional view which shows the reference example of the wheel bearing apparatus which concerns on this invention. It is an enlarged view which shows the hub ring single-piece | unit of FIG. The implementation form of a wheel bearing apparatus of the present invention is a longitudinal sectional view showing. It is an enlarged view which shows the hub ring single-piece | unit of FIG. It is a longitudinal cross-sectional view which shows the conventional wheel bearing apparatus.

Explanation of symbols

1, 18 ... Inner member 2 ... Outer member 3 ... ············································································································· Hub rings 5a, 6a・ ・ ・ ・ ・ ・ ・ ・ ・ Inner rolling surface 5b ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Small diameter step 6 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner ring 6b ················· 6c ·············································· 7 ... Wheel mounting flange 7a ... Hub bolt 7b ... Round hole 7c ... ········· Bases 8 and 21 ·················· Shafts 8a, 16a, 22 ... ... Steps 8b and 15 6 ···· shoulder 9 ······································································・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Seal 13 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Magnetic encoder 14 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・Counter part 17, 20 ............ Recess 23, 24 ............ Hardened layer 50 ............ ..Wheel bearing device 51 ........ Outer member 51a ........ Outer side outer rolling surface 51b ..・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Outer rolling surface 51c on the inner side ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Car body mounting flange 52 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・... Hub wheels 52a, 54a ... Inside rolling surface 52b ... ········ Small diameter step 52c ·················································· Wheel mounting flange 54 ... inner ring 55 ... inner members 56, 57 ... Balls 58, 59 ... Retainer 60, 61 ... Seal d0 ... The groove bottom diameter d1 of the inner raceway surface of the hub wheel ......... the base diameter d2 ......... the hub wheel ball Contact diameter D1 ·········· Pitch circle diameter D2 of outer side ball ········· Pitch circle diameter of inner side ball PCDo ・ ・ ・ ・ ・ ・ ・ ・ Pitch of ball on outer side Circle diameter PCDi ......... Pitch circle diameter t1 of the ball on the inner side ......... Minimum wall thickness t2 of the base ... ·········· Thickness t3 in the contact angle direction of the ball on the hub wheel ································ Minimum thickness α of the recess・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Contact angle

Claims (3)

An outer member integrally having a vehicle body mounting flange to be attached to the knuckle on the outer periphery, and a double row outer rolling surface formed on the inner periphery;
A wheel mounting flange for mounting a wheel at one end is integrally formed, one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and a small diameter step extending in the axial direction from the inner rolling surface A hub ring formed with a portion, and an inner ring that is press-fitted into a small-diameter step portion of the hub ring through a predetermined squeeze and has the other inner rolling surface opposed to the double-row outer rolling surface on the outer periphery. An inner member comprising:
A double row rolling element housed in a freely rolling manner between the rolling surfaces of the inner member and the outer member;
In the wheel bearing device in which a predetermined hardened layer is formed by induction hardening over the small diameter step portion from the inner side base of the wheel mounting flange, including the inner rolling surface of the hub wheel,
Out of the double row rolling elements, the outer side rolling element is a ball and the inner side rolling element is a tapered roller, and the pitch circle diameter of the inner side tapered roller is smaller than the pitch circle diameter of the outer side ball. A shaft-shaped portion extending in the axial direction from the groove bottom portion of the inner raceway surface of the hub wheel to the small-diameter step portion is formed, and the shaft-shaped portion and a shoulder portion that abuts against the inner ring A tapered step is formed between them, and a mortar-shaped recess is formed at the outer end of the hub wheel. The depth of the recess exceeds the groove bottom of the inner rolling surface. The depth to the vicinity of the stepped portion, the thickness of the ball in the contact angle direction on the inner rolling surface is thicker than the thickness of the groove bottom portion of the inner rolling surface, and the depth of the hardened layer The wheel bearing device is set to be twice or more.   2. The wheel bearing device according to claim 1, wherein the thickness of the ball in the contact angle direction of the ball on the inner raceway surface of the hub wheel is set in a range of 0.2 to 0.3 of the diameter of the portion. The inner ring is fixed in an axial direction in a state where a predetermined preload is applied by a crimping portion formed by plastically deforming an end portion of the small diameter step portion radially outward. Wheel bearing device.

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